code: def transparent(red, green, blue, _, opacity=0.5):
      """transparent: converts a rgba color to a transparent opacity"""
      return (red, green, blue, opacity)
  
file_path: dragonfly/dragonfly/utils/plot_utils.py
imports: from __future__ import division
  import pickle
  import argparse
  import matplotlib.pyplot
  import matplotlib
  from scipy.io import loadmat
  import numpy
label_desc: Use image node_id 2 for calling a global function with example usage: transparent(red, green, blue, _, opacity) and returns: red,  green,  blue,  opacity